Reading deficits are very common and persistent following stroke in previously literate adults. Acquired dyslexia occurs in patients with and without other language deficits, but these patients rarely receive dyslexia treatment. Few treatment methods for acquired dyslexia are available, and those treatments that are currently employed are often unsuccessful. One reason for the failure of these treatments is that sources of reading disruption [i.e., the cognitive deficit(s) to be treated] are not specifically defined in the individual dyslexic patients. Progress in the refinement of cognitive theories of normal reading offer hope for more effective dyslexia treatments, in that more specific diagnoses of reading breakdown will be possible: treatment designs can then be focused on remediating these specific levels of reading deficit. The immediate goal of the proposed research is to use a new model of visual word recognition as a basis for diagnosis and treatment of reading deficits in aphasic patients. This new model specifies the critical role of a prelexical Ordinal Graphemic Code in normal reading, and the characteristic error pattern associated with disruption with disruption at this level. New diagnostic methods used to detect this prelexical deficit can now be applied to a wide range of aphasic patients who exhibit similar error patterns in reading. Multiple interrelated experiments will address the following specific aims: 1) to assess in a group of stroke patients with acquired dyslexia the extent to which abnormal function of the Ordinal Graphemic Code is contributing to visual and semantic substitutions in word reading, to errors in orthographic segmenting, and to impaired grapheme-to-phoneme conversion; 2) to assess the extent to which disorders of access to or operation of the Ordinal Graphemic Code in stroke patients are amenable to treatment. Experimental treatment will follow rigorous assessment of reading deficits in aphasic patients with impaired lexical access from print. Those patients with presumed disruption to prelexical ordinal encoding will be entered into treatment, which will measure the effect of systematically varying demand for ordinal encoding in ordinal encoding will also be evaluated, with the prediction that auditory serial letter name cues and/or top-down lexical-semantic cues will contribute to a positive treatment response. The diagnostic and treatment methods advanced here are intended as a model to guide further development and implementation of more effective treatments for language disorders, particularly acquired dyslexia.